The present invention relates to "active" food service systems wherein individual portions of precooked food are supported on trays within movable carts. The carts are placed in a chilled environment to store the food in a chilled state. Selected foods on the trays are rethermalized, or heated to hot serving temperatures, in the cart, while other portions of the foods on the trays remain in the chilled state. The present invention also relates to "passive" food service systems wherein the hot cooked food is served up on plates or trays, covered and then transported to the intended user.
A rethermalization system is a food service system wherein food is cooked or precooked and then chilled in bulk. The food is divided in individual portions and stored in a chilled state until it is reheated. The U.S. Food and Drug Administration (FDA) guidelines specify that the chilled and stored temperature most be 40.degree. F. or less. A short time before the food is served, the food which is to be served hot is brought to a safe reheated temperature; that is, it is rethermalized. FDA guidelines specify that a safe reheating temperature is 165.degree. F. or greater.
One known rethermalization concept is the Temp Rite II System available from Aladdin Synergistics, Inc. of Nashville, Tenn., and is disclosed at least in part in U.S. Pat. No. 4,285,391 to Bourner. The Temp Rite II System uses three separate thermostatically controlled heaters on each cart shelf whereby each heater supplies a particular wattage depending on the type and density of the food to be heated and the dishware used. The Temp Rite II tray has compartments each separated from the others, and a compartmentalized insulated cover is placed over the food compartments thereby isolating the hot areas from the cold areas.
After the trays are assembled on a cold tray line and then protected by the insulated cover tops, the assembled trays are placed on the cart shelves. The trays can be placed in the cart in a first position or in a 180.degree. reverse position. In the first position, the three hot food compartments align precisely with the three heating elements and the cover automatically engages an activator switch mounted on the side of the cart for future heating. If the tray is placed in the reverse position, however, the three hot compartments will not be positioned over the heating elements and the cover will not engage the activator switch. As a result, all the food on the tray remains cold. The loaded carts are then rolled into a rethermalization refrigerator where the meals are held at 40.degree. F. The activator switch turns the three elements either "on" or "off" and does not individually control any one heating element.
Another very recent system is the Temp Rite II Excel System, also available from Aladdin Synergetics, Inc. and disclosed at least in part in the '204 application. It is basically a cafeteria pellet system which utilizes separate hot dishes having separate insulated covers or domes. This system includes a unique separate heating pad arrangement. Each pad is a modular unit and can be replaced if necessary without replacing the other pads on the same tray extrusion. Each pad further incorporates two circuits--a low wattage primary and a higher wattage secondary--which allow for the heating over a wide range and combination of different food densities. A dome sensing magnetic switch determines the presence or absence of the insulated dome over the pad. If the dome is present the pad will be activated to permit heating of the food at the desired time. If the operator wants to keep certain foods cold, the dome can be removed for preventing activation of the pad. Other examples of food service rethermalization systems wherein the heating elements are incorporated into shelves within the service carts are shown in U.S. Pat. Nos. 4,346,756 and 4,323,110.
Thus, with the Temp Rite II carts, meals are assembled cold using advanced prepared foods then held in the carts in dedicated refrigerators. These refrigerators can be either individual roll-in units or central walk-in units for decentralized or centralized application. The centralized rethermalization system accommodates many carts at the same time and is large enough to define a walk-in room. An external control panel has automatic programmable timers which activate the rethermalization sequence in the carts. The carts automatically engage into special electrical receptacles in the back of each roll-in unit, either single bay or double bay units. The walk-in units include modular floor mounted electrical receptacles for automatically engaging in the carts. Immediately before serving, the meals are heated within their insulated enclosures and within the refrigerator and without rehandling. The insulated technology of this system allows each food item to be kept at its proper hot or cold temperature until served. The decentralized option puts the meal service close to the patient by locating the system in a floor galley. The decentralized option utilizes a roll-in refrigerator designed especially for use with these carts. This refrigeration unit maintains the inside air temperatures between 38.degree. and 40.degree. F. before, during and after rethermalization.
As explained in the '204 application, the cart preferably has individual heating pads, one for each of the two separate hot food areas of the tray. Each pad has a built-in light providing a visual indication of whether the heaters are receiving electricity and actually heating. This allows the maintenance personnel and operators to determine whether the heater's heating elements are functioning properly. These light bulbs, however, last only a few weeks while the rest of the cart typically lasts for many years. Thus, when a single light bulb burns out it has been necessary to dispose of the entire heating pad unit at great expense. Even if the pad were designed so that the light bulb could be easily replaced, the time (and thus cost) required for a mechanic to replace them is not insignificant. It is also difficult to determine whether it is the heating element which is not functioning or the light bulb.
Further, these lights are typically not visible during the rethermalization process. When the carts are inside of a walk-in refrigerator they are lined up right beside each other. The operators typically are only able to see the handle part or back of the cart and not the sides since the sides are adjacent and directly facing one another. The lights which are positioned visible only at the sides of the carts thus cannot be seen. For the roll-in refrigerators there are adjacent refrigerator walls on either side which also prevent the lights from being seen, as maintenance personnel or operators cannot stick their heads in far enough to see the lights. Thus the only way to determine whether the unit is heating is to place one's hand on top of the heating element. There are two problems to this. First and obviously, the tester can get burned. Second, there is often a dish on top of the unit so that it cannot be conveniently accessed.
A further problem with this electrical bulb indicator is that once the cart is removed from the refrigerator unit or when the power goes off after the rethermalization cycle is complete, the light is extinguished. Therefore there is no visual indicator of whether the meal is actually heated, the heater has worked or is working properly and so forth. The only way to determine whether there was a successful rethermalization is to actually pull the meal out and look at it to determine whether it is hot enough. In other words, if it is in a roll-in refrigerator the operator cannot see the light so he rolls it out to where he can see it but then the power is disconnected so the light goes off. Thus, without actually taking the meal out and testing it cannot be determined whether sufficient heating thereof has taken place.
A preferred heating element is a two-speed heating element and the light is placed across only one of the electrical lines either the high or the low speed, and preferably the high speed. Thus when the heater has heated to its maximum and is about fifteen minutes into the rethermalization cycle, the heater goes into its low speed or maintenance mode and the light goes out. One who is trouble shooting or checking the unit might thus assume that the heater has actually burned out.
The walk-in rethermalization system typically has a rethermalization cycle of only thirty-six minutes for heating the meals in the cart. When this period has elapsed the control panel on the outside of the unit beeps to indicate the completion of this cycle. The operators then enter the cooler and pick up the carts. A number of banks of carts are typically held in the cooler and the operators may not remember which bank of carts was finished. Since the electricity to the carts is "off" now, the indicator lights are extinguished and there is no immediate indicator alerting the operators as to which of the carts have been properly heated.
The above-described rethermalization system(s) is an "active" system wherein heating of the food takes place with the food in position on the tray. Another food service system also particular useful in institutional settings is a "passive" system wherein the food is heated before being placed on the tray. It is plated hot onto the insulated tray and then covered with an insulating cover to keep it hot while it is transported to the intended consumer. An example of such a system is the Temp Rite I System, another Aladdin food handling system. For this system the plates are heated, the food is heated up on steam tables and the hot food plated onto the hot plates. An insulated cover is placed over the plated food resting on the insulated tray base. This is a passive system; there is no rethermalization of the meal, no electricity is used for the tray system, and the insulation provides a heat maintenance.
The trays, after they have been plated up and covered in the passive system or rethermalized in the active system, are then transported to the location of the intended consumers and may wait twenty, thirty or more minutes before they are actually served or consumed. In satelliting operations the carts and thus trays may also be transported outside where their temperature can be affected by the hot or cold environment. Since the FDA requires that hot food to be edible and safe must be in a safe zone of at least 140.degree. F., the nurse, hostess or other server must at least spot probe the food with some type of device, such as a thermocouple or a thermometer, to determine whether it is not enough. In other words, he or she must lift the cover and stick a food thermometer into the food to spot check to make sure that the meals are still hot. As can be appreciated, this is not only a time consuming and cumbersome process but has sanitation aspects to it as well.